This documentation differs from the official API.Jadeite adds extra features to the API including:
variable font sizes,
constructions examples,
placeholders for classes and methods, and auto-generated “See Also” links.
Additionally it is missing some items found in standard Javadoc documentation, including:
generics type information,
“Deprecated” tags and comments,
“See Also” links,
along with other minor differences.
Please send any questions or feedback to bam@cs.cmu.edu.

A version of {@link AbstractQueuedSynchronizer} in
which synchronization state is maintained as a long.
This class has exactly the same structure, properties, and methods
as AbstractQueuedSynchronizer with the exception
that all state-related parameters and results are defined
as long rather than int. This class
may be useful when creating synchronizers such as
multilevel locks and barriers that require
64 bits of state.

AbstractQueuedLongSynchronizer

protected AbstractQueuedLongSynchronizer()

Creates a new AbstractQueuedLongSynchronizer instance
with initial synchronization state of zero.

Method Detail

acquire

public final void acquire(long arg)

Acquires in exclusive mode, ignoring interrupts. Implemented
by invoking at least once {@link #tryAcquire},
returning on success. Otherwise the thread is queued, possibly
repeatedly blocking and unblocking, invoking {@link
#tryAcquire} until success. This method can be used
to implement method {@link Lock#lock}.

Parameters:

arg - the acquire argument. This value is conveyed to
{@link #tryAcquire} but is otherwise uninterpreted and
can represent anything you like.

acquireInterruptibly

Acquires in exclusive mode, aborting if interrupted.
Implemented by first checking interrupt status, then invoking
at least once {@link #tryAcquire}, returning on
success. Otherwise the thread is queued, possibly repeatedly
blocking and unblocking, invoking {@link #tryAcquire}
until success or the thread is interrupted. This method can be
used to implement method {@link Lock#lockInterruptibly}.

Parameters:

arg - the acquire argument. This value is conveyed to
{@link #tryAcquire} but is otherwise uninterpreted and
can represent anything you like.

acquireSharedInterruptibly

Acquires in shared mode, aborting if interrupted. Implemented
by first checking interrupt status, then invoking at least once
{@link #tryAcquireShared}, returning on success. Otherwise the
thread is queued, possibly repeatedly blocking and unblocking,
invoking {@link #tryAcquireShared} until success or the thread
is interrupted.

Parameters:

arg - the acquire argument.
This value is conveyed to {@link #tryAcquireShared} but is
otherwise uninterpreted and can represent anything
you like.

getExclusiveQueuedThreads

Returns a collection containing threads that may be waiting to
acquire in exclusive mode. This has the same properties
as {@link #getQueuedThreads} except that it only returns
those threads waiting due to an exclusive acquire.

getQueuedThreads

Returns a collection containing threads that may be waiting to
acquire. Because the actual set of threads may change
dynamically while constructing this result, the returned
collection is only a best-effort estimate. The elements of the
returned collection are in no particular order. This method is
designed to facilitate construction of subclasses that provide
more extensive monitoring facilities.

Returns:

the collection of threads

getQueueLength

public final int getQueueLength()

Returns an estimate of the number of threads waiting to
acquire. The value is only an estimate because the number of
threads may change dynamically while this method traverses
internal data structures. This method is designed for use in
monitoring system state, not for synchronization
control.

Returns:

the estimated number of threads waiting to acquire

getSharedQueuedThreads

Returns a collection containing threads that may be waiting to
acquire in shared mode. This has the same properties
as {@link #getQueuedThreads} except that it only returns
those threads waiting due to a shared acquire.

Returns:

the collection of threads

getState

protected final long getState()

Returns the current value of synchronization state.
This operation has memory semantics of a volatile read.

Returns:

current state value

getWaitingThreads

Returns a collection containing those threads that may be
waiting on the given condition associated with this
synchronizer. Because the actual set of threads may change
dynamically while constructing this result, the returned
collection is only a best-effort estimate. The elements of the
returned collection are in no particular order.

Parameters:

condition - the condition

Returns:

the collection of threads

getWaitQueueLength

Returns an estimate of the number of threads waiting on the
given condition associated with this synchronizer. Note that
because timeouts and interrupts may occur at any time, the
estimate serves only as an upper bound on the actual number of
waiters. This method is designed for use in monitoring of the
system state, not for synchronization control.

Parameters:

condition - the condition

Returns:

the estimated number of waiting threads

hasContended

public final boolean hasContended()

Queries whether any threads have ever contended to acquire this
synchronizer; that is if an acquire method has ever blocked.

In this implementation, this operation returns in
constant time.

Returns:

{@code true} if there has ever been contention

hasQueuedThreads

public final boolean hasQueuedThreads()

Queries whether any threads are waiting to acquire. Note that
because cancellations due to interrupts and timeouts may occur
at any time, a {@code true} return does not guarantee that any
other thread will ever acquire.

In this implementation, this operation returns in
constant time.

Returns:

{@code true} if there may be other threads waiting to acquire

hasWaiters

Queries whether any threads are waiting on the given condition
associated with this synchronizer. Note that because timeouts
and interrupts may occur at any time, a true return
does not guarantee that a future signal will awaken
any threads. This method is designed primarily for use in
monitoring of the system state.

Parameters:

condition - the condition

Returns:

true if there are any waiting threads

isHeldExclusively

protected boolean isHeldExclusively()

Returns {@code true} if synchronization is held exclusively with
respect to the current (calling) thread. This method is invoked
upon each call to a non-waiting {@link ConditionObject} method.
(Waiting methods instead invoke {@link #release}.)

The default implementation throws {@link
UnsupportedOperationException}. This method is invoked
internally only within {@link ConditionObject} methods, so need
not be defined if conditions are not used.

Returns:

{@code true} if synchronization is held exclusively;
{@code false} otherwise

toString

Returns a string identifying this synchronizer, as well as its state.
The state, in brackets, includes the String {@code "State ="}
followed by the current value of {@link #getState}, and either
{@code "nonempty"} or {@code "empty"} depending on whether the
queue is empty.

tryAcquire

Attempts to acquire in exclusive mode. This method should query
if the state of the object permits it to be acquired in the
exclusive mode, and if so to acquire it.

This method is always invoked by the thread performing
acquire. If this method reports failure, the acquire method
may queue the thread, if it is not already queued, until it is
signalled by a release from some other thread. This can be used
to implement method {@link Lock#tryLock()}.

arg - the acquire argument. This value is always the one
passed to an acquire method, or is the value saved on entry
to a condition wait. The value is otherwise uninterpreted
and can represent anything you like.

Returns:

{@code true} if successful. Upon success, this object has
been acquired.

tryAcquireNanos

Attempts to acquire in exclusive mode, aborting if interrupted,
and failing if the given timeout elapses. Implemented by first
checking interrupt status, then invoking at least once {@link
#tryAcquire}, returning on success. Otherwise, the thread is
queued, possibly repeatedly blocking and unblocking, invoking
{@link #tryAcquire} until success or the thread is interrupted
or the timeout elapses. This method can be used to implement
method {@link Lock#tryLock(long, TimeUnit)}.

Parameters:

arg - the acquire argument. This value is conveyed to
{@link #tryAcquire} but is otherwise uninterpreted and
can represent anything you like.

tryAcquireShared

protected long tryAcquireShared(long arg)

Attempts to acquire in shared mode. This method should query if
the state of the object permits it to be acquired in the shared
mode, and if so to acquire it.

This method is always invoked by the thread performing
acquire. If this method reports failure, the acquire method
may queue the thread, if it is not already queued, until it is
signalled by a release from some other thread.

arg - the acquire argument. This value is always the one
passed to an acquire method, or is the value saved on entry
to a condition wait. The value is otherwise uninterpreted
and can represent anything you like.

Returns:

a negative value on failure; zero if acquisition in shared
mode succeeded but no subsequent shared-mode acquire can
succeed; and a positive value if acquisition in shared
mode succeeded and subsequent shared-mode acquires might
also succeed, in which case a subsequent waiting thread
must check availability. (Support for three different
return values enables this method to be used in contexts
where acquires only sometimes act exclusively.) Upon
success, this object has been acquired.

tryAcquireSharedNanos

Attempts to acquire in shared mode, aborting if interrupted, and
failing if the given timeout elapses. Implemented by first
checking interrupt status, then invoking at least once {@link
#tryAcquireShared}, returning on success. Otherwise, the
thread is queued, possibly repeatedly blocking and unblocking,
invoking {@link #tryAcquireShared} until success or the thread
is interrupted or the timeout elapses.

Parameters:

arg - the acquire argument. This value is conveyed to
{@link #tryAcquireShared} but is otherwise uninterpreted
and can represent anything you like.

arg - the release argument. This value is always the one
passed to a release method, or the current state value upon
entry to a condition wait. The value is otherwise
uninterpreted and can represent anything you like.

Returns:

{@code true} if this object is now in a fully released
state, so that any waiting threads may attempt to acquire;
and {@code false} otherwise.

arg - the release argument. This value is always the one
passed to a release method, or the current state value upon
entry to a condition wait. The value is otherwise
uninterpreted and can represent anything you like.

Returns:

{@code true} if this release of shared mode may permit a
waiting acquire (shared or exclusive) to succeed; and
{@code false} otherwise

This documentation differs from the official API.Jadeite adds extra features to the API including:
variable font sizes,
constructions examples,
placeholders for classes and methods, and auto-generated “See Also” links.
Additionally it is missing some items found in standard Javadoc documentation, including:
generics type information,
“Deprecated” tags and comments,
“See Also” links,
along with other minor differences.
Please send any questions or feedback to bam@cs.cmu.edu.

This page displays the Jadeite version of the documention, which is derived from the offical documentation that contains this copyright notice: